The Implications of AMD Induced Acidity, High Metal Concentrations and Ochre Precipitation on Aquatic Organisms

Abstract

Acid mine drainage (AMD) is a low pH, high conductivity, high metals, and sulphate ion concentration liquid formed by the oxidation of sulphide minerals in pyrite-bearing mine wastes. The generation of AMD has been associated mostly with coal and gold mining but mining of other sulphidic metal ores such as tin, silver, copper, and iron are also known to generate AMD [1][2][3]. A series of studies [4-9] have reported on AMD generation and the microbes involved in the process with all these studies indicating that AMD forms when sulphide-rich mine wastes get exposed to oxygen-rich conditions. Sulphur containing minerals associated with the generation of AMD according to Li et al. [10] and Chopard et al. [11] include pyrite (FeS 2 ), arsenopyrite (FeAsS), chalcopyrite (CuFeS 2 ), galena (PbS), gersdorffite (NiAsS), pyrrhotite, and sphalerite